In a battle over who will take control of the heart of the island, Locke claims he can sink the island and get away while Jack swears he'll kill him first. Knowing Desmond is the key, they lower him into the source of the light, where his actions extinguish the glow and trigger a series of earthquakes that knock him unconscious and seem destined to destroy the island. No longer invincible, Locke tries to escape only to have Jack catch up to him and push him off a cliff, but not before Locke manages to stab him. Elsewhere on the island, Miles is reunited with Richard Alpert and Frank Lapidus who informs them he can he can fly them away on the plane. They have to move quickly, though, since the island is shaking so hard, it's falling apart. When the others hear of this, Kate tries convincing Jack to join them, but he insists he must reverse what Desmond did. While Kate, Sawyer and Claire race for the plane and catch it just before it takes off, Hurley and Ben accompany Jack back to the heart of the island. There, Jack anoints Hurley keeper of the island before Hurley and Ben lower him down the shaft. Jack arranges for Desmond's rescue and manages to return the island to normal but is too injured to get himself out. Aboveground, Hurley is left with the sobering thought that Jack sacrificed himself for everyone else and he is now in charge. In the flash sideways, everybody is starting to realize his or her true purpose. Hurley and Desmond do their part rounding up everyone; Sun and Jin remember their travails on the island; Sawyer and Juliet meet, seemingly for the first time, then recall their love; Sayid is reunited with Shannon and Charlie with Claire. John Locke awakens from surgery, finds himself completely healed. Jack is the only one who refuses to accept the meaning of the flashbacks. Jack runs into Kate who leads him to a church where she encourages him to join her and the others inside when he's ready. There, he encounters his father, who explains that Jack has passed away, as has all his island compatriots. The sideways world is a way station that allows them to remember and connect with the people who meant the most to them. Now that they've all found each other once again, it's time to let go and move on. Jack joyously reunites with every significant figure he knew on the island, whereupon Christian opens the double doors of the nave, flooding the space with light. Back on the island, a mortally wounded Jack emerges from the heart of the island, stumbles through the bamboo forest and finally collapses onto his back. He watches his friends fly away on the plane before his eyes close.